Formation of bifurcated tubing



March 28, 1961 A. HUET FORMATION OF BIFURCATED TUBING 3 Sheets-Sheet 1 Filed June 14, 1955 In! Mu FIG. 5

\ lllllll ll ilriliialiil lllilllu'lll ll IVIll FIG. 4 a l A INVENTOR: ANDRE HUET RNEY March 28, 1961 A. HUET FORMATION OF BIFURCATED TUBING 3 Sheets-Sheet 2 Filed June 14, 1955 rlvniviliillilttvn.

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ATTORNEY March 28, 1961 A HUET 2,976,606

FORMATION OF BiFURCATED TUBING Filed June 14, 1955 3 Sheets-Sheet 3 INVEEJVTOR ANDR HUET Win ATT RNEY hire FORMATION OF BIFURCATED TUBING Andr Huet, Paris, France, assignor to Combustion Engineering, Inc., New York, N.Y., a corporation of Delaware The present invention relates to metal working and particularly to the manufacture of bifurcated tubes with specific reference to their formation from tubing previously bent to U-shape with parallel branches.

The present invention relates to the fashioning of a branch bend, i.e. a bend having a connection in the bent portion giving it ultimately the shape of a Y, by compressing a tube bend (of radius initially greater than that of the final branch bend which it is desired to obtain) between suitably contoured and conformed dies so as to eifect, during the operation of bringing the branches together, an upsetting of metal from the bend to create a protuberance on the elbow where the branch is to be formed.

It is known that the radius of a 180 hairpin tube bend may be diminished by compression of such bend between dies, usually with parallel faces, which bring together the straight branches of the bend, the operation being preceded by careful heating of certain portions of the bend to be treated. However, such operations merely narrow the spacing of the tube legs of the bend and do not result in forming a protuberance on the elbow.

According to the invention, the original workpiece is a tube bend which may be heated to a suitable temperature in the outer portion of the bend and to a higher temperature at the point where the branch is to be made. The bend is then placed between two dies so shaped as to present a slight shoulder towards the outer portion of the bend. These half-dies are so formed that when brought together an opening is left between them where the outer portion of the bend or elbow is located; into this opening metal is bulged from the bend by compression to form a bulge or protuberance which is afterwards opened and shaped into a branch.

In a variant of the method, instead of compressing the original bend as is, an opening is first made in the outer portion of the bend at the point where the branch is wanted. A mandrel may then be introduced into this opening prior to the operation of compressing between the half-dies, so as to prevent thickening of the wall in the crotch portion of the bend and cause the bulged metal to travel along the said mandrel and form the branch immediately during the compression operation.

The following description, referring to the accompanying drawings offered by way of example, will more clearly show how the invention may be practiced.

Fig. 1 shows a 180 tube bend that is to be processed to form a branched tube such as a bifurcate.

Fig. 2 shows the same bend placed between the dies that are to compress it.

Fig. 3 shows the bend of Fig. 2 after compression.

Fig. 4 is an end view of Fig. 3 looking toward the elbow of the bend;

Fig. 5 is a longitudinal sectional view made in accordance with the invention.

Fig. 6 is a sectional view of a bend to be processed in accordance with a variation of the method constituting the invention.

2,976,606 Patented Mar. 28, 196.1

that merge into the crotch and elbow spaced apart slightly greater than the tubes of the branch bend ultimately de sired. The bend, optionally filled with sand, is heated to a suitable temperature in the shaded region A of Fig. 1. The cross-shaded region B corresponding to the portion of the bend where it is desired to make the branch is heated to a higher temperature. Zones D and C located in the inner portion of the bend may also be heated.

The bend, held between two parallel flat plates 2 and 3 (Fig. 4), is placed between two sliding dies 4 and 5 which strike the straight tube legs of the bend as shown in Fig. 2 and which have a contoured portion E extend ing beyond the bend to form the bulged metal. The inner portion of the bend may be supported with the aid of a die 6 placed as shown in Fig. 2 between the tube legs of the bend and bearing on the inner portion of the latter. This die 6 is fixed to the platform or working surface.

The two dies 4 and 5 can come together in the direction of the arrows F in Fig. 2 so as to compress the bend and cause bulging of metal at 7 to form a bulge protruding from the end of the elbows, as shown in Fig. 3. The dies 4 and 5 are so shaped as to leave between them, in their position of closest approach, an opening 8 as shown in Fig. 4, in which the bulge, for example of circular cross section, is formed. This bulge need only be opened,

as shown in Fig. 5, to obtain a bend with branch 9. Optionally, the branch 9 may be further shaped and finished to the dimensions or" the final branch which it is desired to obtain.

In a variant of the method, the original bend 1 to be processed is provided with an opening 10, preferably circular, as shown in Fig. 6, at the point where it is desired to make the branch. The presence of such an opening may facilitate the bulging of metal into the form of a branch during compression. Optionally, during the operation of compression, the opening 10 may also be fitted with a shaped mandrel 11 as shown in Fig. 7, so that under the compression exerted in the direction of arrows F by dies 4 and 5, the bulged metal of the bend will move as shown in Fig. 8 along the mandrel 11 to form a branch 12 directly. Further, the mandrel 11, holding between it and die 6 (when a die such as 6 is used, which may not be essential) the meal of the bend in the inner portion G thereof, prevents thickening of the metal in such portion G during closing of the dies, and the excess metal resulting from the compression will flow towards the outer portion of the bend so as to provide a branch 12 with a higher edge.

As is shown in Figs. 9 to 11, one may start with a bend 1 already provided with a bulb 13 on the elbow of the bend, formed, for example, as disclosed in my earlier United States Patent 2,763,917 dated September 25, 1956.

Such a bend is placed between two dies 4 5 which may be brought together in the direction of arrows F, and for example having oblique faces relative to the direction of the straight branches of the bend 1, so that compression will be exerted first in the already bent portion of the bend 1, as indicated in Fig. 10. Between the straight branches of the bend, there is an auxiliary die 6 of form corresponding to the oblique faces of dies 4 5 After closure of the dies, with resulting bulging of metal into the existing bulged portion, a bend is obtained, as shown in Fig. 11, having a much enlarged protuberance or bulge 13 which may readily be converted into a branch somewhat longer than in Fig. 5, by opening it at the end.

The possibly somewhat oblique branches of the bend 1 may be made parallel once more after the operation has been completed.

Obviously, a previously opened bulge 13 may be processed in the manner described with reference to Figs. 6 to 8. In that case, a punch 11 may be used which, passing through the opening in the bulb, will act in conjunction with the die 6 as in the case of the said figures to yield ultimately a similar relatively long branch.

The oblique-bearing dies 4 5 may further be articulated so as to straighten in the course of compression and ultimately occupy the so-called parallel position illustrated in Figs. 3 to 8, in which their bearing surfaces again become parallel to the direction of the straight branches of the bend.

Of course, variations in detail may be made in the embcdiment of this invention without thereby transcending its scope.

What I claim is:

1. The method of forming a tubular bifurcate comprising: providing a tube bend having the tube legs that merge into the crotch and elbow region of the bend spaced apart a distance greater than the desired spacing of the tube legs of the bifurcate; heating the bend in the outer elbow region to a higher temperature than in the opposite crotch region; applying forces acting in opposite directions on the outer side of the tube legs contiguous to the elbow by means of an instrumentality having work faces shaped to contour of tube legs and partially embracing the latter, said faces being inclined outwardly away from the axes of the tube legs so that the application of said forces in addition to reducing the spacing of the. tube legs efiects a displacement of the heated material in a direction outwardly of the elbow to create a bulge on said elbow; laterally confining the said bulge formed on the elbow by members contacting it at the sides and shaping it to form a tubular cylindrical protuberance extending outwardly from the elbow.

2. The method of forming a tubular bifurcate comprising; providing a tube bend having the tube legs that merge into the crotch and elbow region of the bend spaced apart a distance greater than the desired spacing of the tube legs of the biturcate; heating the bend in the outer elbow region to a higher temperature than in the opposite crotch region; applying forces acting in opposite directions on the outer side of the tube legs contiguous to the elbow by means of an instrumentality having work faces shaped to contour of tube legs and partially embracing the latter, said faces being inclined outwardly away from the axes of the tube legs so that the application of said forces in addition to reducing the spacing of the tube legs effects a displacement of the heated material in a direction outwardly of the elbow to create a bulge on said elbow; laterally confining the said bulge formed on the elbow by members contacting it at the sides and shaping it to form a tubular cylindrical protuberance extending outwardly from the elbow; and forming an opening in the end face of said protuberance to provide for connection of a tube in fluid communication with the said bifurcate.

3. The method of forming a tubular bifurcate comprising: providing a tube bend having the tube legs that merge into the crotch and elbow region of the bend spaced apart a distance greater than the desired spacing of the tube legs of the bifurcate; heating the bend in the outer elbow region to a higher temperature than in the opposite crotch region; applying forces acting in opposite directions on the outer side of the tube legs contiguous to the elbow by means of an instrumentality having work faces shaped to the contour of tube legs to partially embrace the latter and in portions engageable with the elbow, being inclined outwardly away from the axes of the tube legs so that the application of said forces in addition to reducing the spacing of the tube legs effects a displacement of the heated material in a direction outwardly of the elbow to create a bulge thereon; confining the said bulge formed on the elbow by members contacting it at the sides and shaping it to form from said bulge a tubular cylindrical protuberance extending outwardly from the elbow; and forming an opening in the end face of said protuberance to provide for connection of a tube in fluid communication with the said bifurcate.

References Cited in the file of this patent Austria June 10, 1955 

